WO2003027341A1

WO2003027341A1 - Magnesium base composite material

Info

Publication number: WO2003027341A1
Application number: PCT/JP2002/002968
Authority: WO
Inventors: Katsuyoshi Kondoh; Tatsuhiko Aizawa; Hideki Oginuma; Eiji Yuasa
Original assignee: Center For Advanced Science And Technology Incubation, Ltd.
Priority date: 2001-09-25
Filing date: 2002-03-27
Publication date: 2003-04-03
Also published as: US20050016638A1

Abstract

A method for producing a magnesium base composite material, which comprises a step of compounding a matrix powder having Mg with a Si powder to provide a mixed powder, a step of packing a container with the mixed powder and apply a pressure to the powder so as to prepare a compact formed article having a porosity of 35 % or less, and holding the compact formed article at an elevated temperature in an inert gas atmosphere or in vacuum, to thereby form Mg2Si. A magnesium base composite material produced by the above powder metallurgical method is suppressed in the growth of a magnesium crystal grain as a matrix or a Mg2Si particle to a coarse one, and as a result, exhibits excellent mechanical properties such as strength and hardness.

Description

Specification

Magnesium-based composite materials

The present invention relates to a magnesium-based composite material having excellent mechanical properties and corrosion resistance, a precursor of the magnesium-based composite material as a precursor thereof, and a method for producing the same. Background art

Research for conventionally magnesium silicide (M g ₂ S i) magnesium particles dispersed matrix composite, are vigorously pursued. For example, JP-A-6 - 8 1 0 6 8 publication is that the M g ₂ S i by reaction with high S i of Matorittasu magnesium alloy containing in you injection molding a semi-molten state M g and S i It discloses a method for producing a magnesium-based composite material which is synthesized and in which the Mg ₂ Si particles are dispersed. Japanese Patent Application Laid-Open No. 8-41564 discloses a magnesium-based composite material in which Mg ₂ S i particles and S i C particles are dispersed by a forging method. Further, JP-2 0 0 0 - 1 7 3 5 2 discloses the spherical M g ₂ S i particles discloses magnesium-based composite material dispersed, and the process according to the鎵造method. DISCLOSURE OF THE INVENTION.

However, the above-mentioned production methods for the magnesium-based composite material are all based on a dissolution method such as a mirror manufacturing method or an impregnation method. That is, in these methods, a magnesium or a magnesium alloy constituting the matrix is once melted and then solidified and solidified. For this reason, the crystal grain size of magnesium in the matrix and the coarse growth of Mg ₂ Si particles are observed, and the resulting reduction in mechanical properties such as strength and hardness is observed. '

In addition, the production method based on the above-described dissolving method itself had an issue of cost inevitably increasing energy consumption.

It is an object of the present invention to provide a crystal grain size and a Mg ₂ Si grain size of a matrix magnesium. An object of the present invention is to provide a high-base composite material which suppresses coarse growth of the element and thereby has high mechanical properties such as strength and hardness and corrosion resistance.

Another object of the present invention is to provide a method for producing a magnesium-based composite material which is lower in cost than the above-mentioned dissolving method in addition to or in addition to the above-mentioned objects. It is a further object of the present invention to provide a precursor of the magnesium-based composite material and a method for producing the same, in addition to or in addition to the above objects.

As a result of intensive studies, the present inventors have found that the above-mentioned problems can be solved by a method for producing a magnesium-based composite material based on a powder metallurgy method, instead of a conventional structure melting method.

In one aspect of the present invention, the present inventors mechanically destroyed / divided an oxide film (MgO) on the surface of Mg powder during the process of compacting a mixed powder of a matrix powder containing Mg and Si powder. By increasing the contact area between the active Mg nascent surface and the Si powder, it was found that both reactions proceed in the solid phase temperature range below the melting point of Mg. Based on this finding, by dispersing the Si powder on the surface and inside or inside the matrix powder containing Mg, there is no MgO between the Si powder and the matrix powder containing Mg, It was found that the adhered state was established, and the reaction between Mg and Si proceeded more easily. '

Specifically, the present inventors have found the following invention.

<1> a step of blending a matrix powder having magnesium (Mg) and silicon (S i) powder to prepare a mixed powder; filling the mixed powder into a container and pressurizing to increase the porosity. A step of producing a green compact of 35% or less; and heating and maintaining the green compact in an inert gas atmosphere or vacuum, and by reacting magnesium in the matrix powder with Si powder, magnesium silicide ( A method for producing a magnesium-based composite material, comprising: producing Mg ₂ S i).

<2> In the above method <1>, Mg ₂ Si is preferably dispersed in a magnesium-based composite material.

<3> In the preparation step of the above method 1) or <2>, (weight of Si powder) Z (weight of Mg in the matrix powder) is preferably 36.6 / 63.4 or less. Or less than 10Z90. <4> In any one of the above methods <1> to <3>, heating is preferably performed at 350 ° C or higher.

<5> In any one of the above methods 1> to <4>, Mg ₂ Si is 3 wt% or more, preferably 5 wt% or more when the magnesium based composite material is 100 wt%. There should be.

<6> A precursor of a magnesium based composite material obtained by mixing a matrix powder containing magnesium (Mg) and a silicon (Si) powder, wherein the precursor has a porosity of 35% or less. A magnesium-based composite precursor.

<7> In the above item <6>, the precursor exhibits an exothermic peak derived from Mg ₂ Si at a temperature of 150 to 650 ° C, preferably 350 to 650 ° C in a differential scanning calorimetry (DSC) measurement. It is better to have.

<8> In the above item <6> or <7>, the precursor preferably has (weight of Si powder) / (weight of Mg in the matrix powder) of 36.6 / 63.4 or less.

<9> A magnesium-based composite material precursor obtained by blending a matrix powder having magnesium (Mg) and a silicon (Si) powder, wherein the precursor is a differential scanning calorimeter (DSC). ) A magnesium-based composite material precursor having an exothermic peak derived from Mg ₂ Si at 150 to 650 ° C, preferably 350 to 650 ° C in the measurement.

<10> In the above item 6>, the precursor preferably has a ratio of (weight of Si powder) / (weight of Mg in the matrix powder) of 36.6 / 63.4 or less.

<11> A step of preparing a mixed powder by blending a matrix powder containing magnesium (Mg) and a silicon (Si) powder; and filling the mixed powder into a container and pressing the container to make it empty. A method for producing a magnesium-based composite material precursor, comprising a step of producing a magnesium-based composite material precursor having a porosity of 35% or less.

1 2> In the preparation step of the method 1 1> above, (weight of Si powder) no (weight of Mg in the matrix powder) is 36.6 / 63.4 or less, preferably 10/90 or less. It is good.

<13> A magnesium-based composite material in which magnesium silicide (Mg ₂ S i) is dispersed in a matrix having magnesium (Mg). A magnesium-based composite material having at least one property selected from the following A) and B):

A) The magnesium-based composite material has a Rockwell hardness (E scale) of 40 or more and 105 or less, preferably 40 or more and 95 or less, and / or the Rockwell hardness (E scale) of the magnesium-based composite material. Is larger than the Rockwell hardness (E scale) of the base material excluding the magnesium silicide of the magnesium-based composite material by a value of 20 to 80, preferably 20 to 40;

B) a force wherein the tensile strength of the magnesium-based composite material is 10 OMPa or more and 35 OMPa or less, preferably 10 OMPa or more and 28 OMPa or less; and Z or the tensile strength of the magnesium-based composite material is the base material. The tensile strength is greater than 2 OMPa and less than 10 OMPa, preferably greater than 2 OMPa and less than 5 OMPa.

<14> In the above <13>, Mg ₂ S i should be at least 3 wt%, preferably at least 5 wt ° / ₀ , when the magnesium-based composite material is 100 w 1:%. ,.

<15> a step of blending a matrix powder containing magnesium (Mg) and silicon (S i) powder to prepare a composite powder in which Si is dispersed in the matrix powder; and A method for producing a magnesium-based composite material, comprising a step of generating magnesium silicide (Mg ₂ S i) by heating and holding in an inert gas atmosphere or vacuum.

<16> In the above item <15>, after the preparation step, the method may further comprise a step of filling the composite powder into a container and pressurizing to produce a green compact, and heating and holding the green compact to form a magnesium compact. The method should preferably include a step of producing mussilide (Mg ₂ S i).

<17> In the above item <15> or <16>, Mg ₂ Si is preferably dispersed in a magnesium-based composite material.

<18> In any one of the above items 15> to 17>, the preparing step may include: a) a step of mixing the Si powder and the matrix powder to obtain a compounded powder; and b) compounding It is preferable to have a step of crushing and / or pressing and / or crushing the powder.

<19> In the above <18>, the preparation step is preferably performed by repeating step b) a plurality of times. <20> In the above <18> or <19>, it is preferable that the step b) in the preparation step is performed using a crusher.

<21> In the above item <20>, the crusher preferably has a mechanical crushing treatment capacity using impact energy by ball media.

<22> In the above item <20> or <21>, the crusher may be selected from the group consisting of a rotary pole mill, a vibrating pole mill, and a planetary pole mill.

<23> In any one of the above <15> to <22>, in the preparation step, (weight of Si powder) Z (weight of Mg in matrix powder) may be 36.6 / 6/3.

It is better to be 4 or less.

<24> In any one of the above <15> to <23>, the heating may be performed at 150 to 650 ° C, preferably at 150 to 350 ° C.

In any one of <2 5> above rather 1 5> ~ <24>, Mg 2 S i , when it has a mug Neshiumu based composite material as 100 wt%, 3 wt% or more, preferably 5 wt% or more Is good.

<26> A magnesium-based composite material precursor obtained by mixing a matrix powder containing magnesium (Mg) and a silicon (Si) powder and dispersing the Si powder in a matrix powder.

<27> In the above item <26>, the precursor may have an exothermic peak derived from Mg ₂ Si at a temperature of 150 to 650 ° C, preferably 150 to 350 ° C in a differential scanning calorimetry (DSC) measurement. It's good to have it.

<28> In the above <26> or <27>, the precursor may have a (weight of Si powder) Z (weight of Mg in the matrix powder) of 36.6 / 63.4 or less. Is good.

<29> A magnesium-based composite material precursor obtained by mixing a matrix powder having magnesium (Mg) and a silicon (S i) powder, wherein the precursor is characterized by differential scanning calorimetry (DSC) In the measurement, the exothermic peak derived from Mg ₂ Si is 150 to 650 ° C., preferably 150 to 350. Magnesium-based composite material precursor contained in C.

<30> In the above item <29>, the precursor is (weight of Si powder) / (matrix (Weight of Mg in the powder) should be 36.6 / 63.4 or less.

<31> a step of blending a matrix powder containing magnesium (Mg) with silicon (S i) powder to prepare a composite powder in which Si is dispersed in the matrix powder; and A method for producing a magnesium-based composite material precursor, comprising a step of filling a container and pressurizing to produce a magnesium-based composite material precursor.

<3 2> In the above item 3 1>, the preparation step includes: a) a step of blending the Si powder and the matrix powder to obtain a blended powder; and b) pulverizing the blended powder and applying Z Alternatively, a step of crushing may be provided.

3 3> In the above 3 2>, the preparation step should be repeated b) several times.

<34> In the above <32> or <33>, the step b) of the preparation step may be performed using a pulverizer.

<35> In the above item <34>, the crusher preferably has a mechanical crushing capacity using impact energy by ball media.

<36> In the above item <34> or <3>, the crusher is preferably selected from the group consisting of a rotary ball mill, a vibrating pole mill, and a planetary ball mill.

<37> In any one of <31> to <36> above, in the preparation step, (weight of Si powder) Z (weight of Mg in the matrix powder) is 36.6 / 6 3.

It is better to be 4 or less.

38> A magnesium-based composite material in which magnesium silicide (Mg ₂ Si) is dispersed in a matrix containing magnesium (Mg), and at least one selected from the following A) and B): Magnesium based composites with different properties:

A) The magnesium-based composite material has a Rockwell hardness (E scale) of 40 or more and 105 or less, preferably 40 or more and 95 or less; and Z or the Rockwell hardness (E) of the magnesium-based composite material. Is larger than the Rockwell hardness (E scale) of the base material excluding the magnesium silicide of the magnesium-based composite material by a value of 20 to 80, preferably 20 to 40; and

B) The tensile strength of the magnesium-based composite material is 10 OMPa or more and 35 OMPa Or less, preferably not less than 10 OMPa and not more than 28 OMPa, and / or the tensile strength of the magnesium-based composite material is not less than 2 OMPa and not more than 10 OMPa, preferably not more than 2 OMPa, than the tensile strength of the base material. Greater than a and less than 5 OMPa.

<39> In the above item <38>, Mg ₂ Si may be at least 3 wt%, preferably at least 5 wt%, when the magnesium-based composite material is 100 wt%. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic diagram of a mixed powder in which a matrix powder containing Mg and a silicon Si powder are uniformly mixed.

FIG. 2 is a graph showing the results of differential calorimetric analysis (DSC) of a compact having a certain porosity.

FIG. 3 is a schematic diagram of a composite powder of the present invention in which silicon Si powder is dispersed in a matrix powder containing Mg.

FIG. 4 is a view showing an image of the composite powder of the present invention observed by an optical microscope.

FIG. 5 is a graph showing the results of DSC measurement of three samples. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail.

According to the present invention, in one aspect, as described above, an oxide film existing on the surface of Mg contained in the matrix powder, that is, a state in which Mg and Si powder are brought into close contact with each other without the presence of MgO is adjusted. The feature is that the reaction between Mg and Si proceeds more easily.

One aspect of the present invention will be described in the order of a method for manufacturing a magnesium-based composite material precursor, an obtained precursor, a method for manufacturing a magnesium-based composite material from the precursor, and an obtained magnesium-based composite material. I do. Further, other aspects of the present invention will be described in the same order as described above.

Magnesium-based composite material precursor according to one aspect of the present invention (hereinafter, unless otherwise specified, The abbreviated precursor) has a step of preparing a mixed powder and a step of pressing the mixed powder to produce a precursor.

In the step of preparing a mixed powder, a matrix powder comprising magnesium (Mg) and a silicon (S i) powder are blended to prepare a mixed powder.

As the matrix powder having Mg, it is preferable to use a powder having a particle diameter of 10 μπι or more from the viewpoint of explosion protection against dust explosion and the like. If this point is satisfied, the form of the matrix powder containing Mg is not particularly limited, but is preferably in the form of, for example, a powder, a chip, or a lump.

In addition, the matrix powder containing Mg includes an alloy containing Mg, or a powder composed of only Mg.

When the matrix powder containing Mg is an alloy, Al, Zn, Mn, Zr, Ce, Li, Ag and the like may be included in addition to Mg. Yes, but not limited to.

The Si powder has a particle size of 10 to 50 m, preferably from 50 to 50 m, in terms of improving mechanical bonding with a matrix powder containing Mg in a step of producing a green compact or a precursor. It should be between 10 and 200 m.

In the preparation process, the ratio of the weight of Si to the weight of Mg contained in the matrix powder, that is, (weight of Si powder) / (weight of Mg in matrix powder), 36.6 / 63.4 It should be: If the added amount of Si exceeds 36.6% by weight, theoretically all of the Mg in the matrix powder becomes Mg ₂ Si (that is, Mg as a matrix does not remain). The material obtained in this case has a significantly lower strength and does not have the desired properties. Therefore, (weight of Si powder) Z (weight of Mg in matrix powder) Force 36.6 / 63.4 or less, preferably 10/90 or less from the viewpoint of mechanical properties and machinability There should be.

A mixed powder is prepared by blending the above matrix powder containing Mg and silicon Si powder. For mixing, a conventional mixing and crushing machine can be used. For example, a V-type mixer or a pole mill can be mentioned, but not limited thereto.

The mixing can be performed in various environments, for example, in the atmosphere. Preferably, fine particles When a powder is used, it is preferable to prevent the oxidation of the powder surface during the mixing process by filling the mixing vessel with an inert gas such as nitrogen gas or argon gas.

By performing the above mixing, as shown in FIG. 1, a mixed powder in which a matrix powder containing Mg and a silicon Si powder are uniformly mixed can be obtained. Next, the obtained mixed powder is filled in a container and pressurized to produce a magnesium-based composite material precursor or a green compact having a porosity of 35% or less.

As a method for solidifying a precursor or a green compact to obtain a green compact, a process used in a conventional powder metallurgy method can be applied. For example, a method in which a container is filled with a mixed powder and cold isostatic pressing (CIP) is performed; or a method in which a powder is filled in a mold and compressed by upper and lower punches to create a green compact; But not limited to these.

The obtained precursor or green compact has a porosity of 35% or less, preferably 20% or less. The significance of setting the porosity to this value is considered to be due to the following effects. That is, the surface of the matrix powder is generally covered with an oxide film (MgO). Since this MgO has a small free energy of formation compared to other oxides and is stable, this MgO surface film suppresses the reaction between Mg and Si powder. For this reason, in the conventional method, a step of generating a liquid phase of Mg by heating above the melting point of Mg (650 ° C) is provided, and then the reaction between the Mg in the matrix powder and the Si powder is promoted. Mg ₂ Si was synthesized. In this heating step, there was a problem of the same matrix and coarse growth of Mg ₂ Si as in the structure melting method.

On the other hand, in the present invention, in the step of producing a precursor or a green compact, the mixed powder is pressurized so that the porosity is 35% or less. In this process, the surface of the MgO surface film is mechanically cut and broken by the plastic deformation of the particles due to the surface friction due to the rearrangement of the particles between the powders, and a new surface of active Mg matrices appears in that part. The new Mg surface is then heated and heated to react with the Si powder to synthesize Mg ₂ Si. Here, the lower the value of the porosity, the larger the area of the Mg nascent surface, and consequently the synthesis temperature of Mg ₂ Si shifts to a lower temperature side. Therefore, the porosity of the precursor or the green compact is preferably lower, more preferably 20% or less. Conversely, the porosity of the precursor or powder compact increases. In this case, the area of formation of the new Mg surface becomes smaller because the MgO film is not destroyed by more than + minutes. As a result, Mg ₂ S i synthesis temperature is hotter side, for example, forced to shift to above the melting point of the liquid phase region of the Mg, that Do and that with the formation of coarse Mg ₂ S i particles.

Magnesium-based composite material precursor or green compact A>

The magnesium-based composite material precursor or green compact according to one aspect of the present invention has the above porosity. This porosity can be measured as follows.

First, the density (A) is determined from the density, composition, and composition of the elements constituting the precursor or the green compact. Further, the density (B) of the obtained precursor or green compact is measured in accordance with JIS Rl643. Using these A and B, the porosity (V) can be obtained by the following equation I.

V = 100- {100 X (B / A)} (Formula I)

In this specification, “porosity” refers to a value obtained by this measurement method, unless otherwise specified.

The magnesium-based composite material precursor or the green compact of the present invention has a value of 150 to 650 as measured by differential scanning calorimetry (DSC). It should have an exothermic peak at C, preferably at 350 to 650 ° C.

As an example, FIG. 2 shows the results of measurement of the precursor or the compact of the present invention prepared under the condition of changing the porosity by differential calorimetry (DSC). Precursors with porosity of 9%, 19% and 32% have an exothermic peak in the above mentioned range, i.e. 150-650 ° C, preferably 350-650 ° C, No endothermic peak is observed. As will be described later, Mg ₂ Si is synthesized by the reaction of Mg and Si in the solid state at this exothermic peak.

On the other hand, in the precursor with a porosity of 52%, an endothermic peak due to the appearance of the liquid phase of Mg is observed at the melting point of Mg (650 ° C). In this case, Mg ₂ Si is synthesized in a liquid state.

Temperature with the highest heating value as the porosity of the precursor or the green compact is lowered (temperature of heat generation peak)., I.e. synthesis initiation temperature of Mg ₂ S i is shifted to the low temperature side. The temperature with the highest calorific value (exothermic peak temperature) is lower than the melting point of Mg (650 ° C) Means that the synthesis reaction is completed in the solid state.

By heating the precursor or the compact, the Mg ₂ Si is generated by the reaction between the Mg in the matrix powder and the Si powder, and the magnesium-based composite material of the present invention is obtained.

The heating atmosphere is not particularly limited. However, in order to suppress the oxidation of Mg or the Mg-containing alloy in the matrix (precursor or green compact), the heating atmosphere is in an inert gas atmosphere such as nitrogen or argon, or in a vacuum. Is good.

As can be seen from the results shown in FIG. 2, the heating temperature is set to 150 ° C. or higher, preferably 350 ° C. or higher, and more preferably 450 ° C. or higher. In order to synthesize Mg ₂ Si in a relatively short time, it is desirable to set the heating temperature to 450 ° C or higher. Accordingly, the present invention mechanically divides and / or breaks the surface oxide film (MgO) during compaction, and as a result, the temperature range is lower than the temperature range of the conventional manufacturing method, namely, 650. . Mg ₂ Si can be synthesized in a temperature range lower than C.

<Magnesium-based composite material A>

The Mg ₂ Si thus obtained has the following characteristics. .

The particle size of Mg ₂ Si is 10 to 200 πι, and the Mg ₂ Si particles are formed in a state of being dispersed in the obtained magnesium based composite material.

In general, Mg ₂ Si has a lower coefficient of thermal expansion than magnesium, has high rigidity and high hardness, and has low specific gravity and excellent heat resistance and corrosion resistance.

Therefore, having the above-mentioned properties of Mg ₂ Si, the obtained magnesium-based composite material of the present invention has excellent properties, for example, mechanical properties and corrosion resistance. When the composite material having these excellent properties contains 100 wt% of Mg ₂ Si in the composite material, the content is preferably 3 wt% or more, and more preferably 5 w 1;% or more.

In particular, the composite material of the present invention has a property of any one of the following A) and B) or a property obtained by variously combining two or more properties.

A) i) a force in which the Rockwell hardness (E scale) of the magnesium-based composite material is 40 or more and 105 or less, preferably 40 or more and 95 or less; and Z or ii) The rock hardness (E scale) of the magnesium-based composite material is 20 or more and 80 or less, and preferably 20 or less, than the mouth hardness (E scale) of the base material obtained by removing the magnesium silicate from the magnesium-based composite material. Greater than or equal to 40 and less; and

B) i) the tensile strength of the magnesium-based composite material is l O OMPa or more and 350 MPa or less, preferably 10 OMPa or more and 28 OMPa or less; and Z or ii) the magnesium-based composite material The tensile strength is greater than the tensile strength of the base material by a value of 2 OMPa to 10 OMPa, preferably 2 OMPa to 5 OMPa.

More specifically, the composite material of the present invention satisfies A_i), A-ii), A-i) with respect to A and satisfies A-ii), and has any property; and Z or , B have any of the characteristics satisfying B-i), B-ii), B-i) and satisfying B-ii). Further, the composite material of the present invention can also have a property that satisfies any of the properties regarding A and any of the properties regarding B at the same time.

According to another aspect of the present invention, a method for producing a precursor of a magnesium-based composite material (hereinafter abbreviated as “precursor” unless otherwise specified) includes a step of preparing a composite powder and a step of pressurizing the composite powder to produce a precursor. And

In the step of preparing a composite powder, a matrix powder comprising magnesium (Mg) and a silicon (Si) powder are blended to prepare a composite powder in which Si is dispersed in a matrix powder.

The particle size and shape of the matrix powder and the Si powder containing Mg are not particularly limited. This is because, as described later, if a process of mechanically pulverizing, mixing, and pressing the mixed powder of both is provided, even if the sample is a coarse powder or a small piece, the Mg and the Si powder are brought into close contact with each other. This is because a state can be formed. However, as the matrix powder containing Mg, it is preferable to use a powder having a particle diameter of 10 m or more from the viewpoint of explosion protection against dust explosion and the like. In addition, the particle size of the matrix powder containing Mg is determined in terms of flowability and Z or a green compact having a uniform density distribution. From the viewpoint of forming the (precursor), the thickness is preferably 50 m or more and 700 m or less, more preferably 150 μm or more and 500 μm or less. Further, the form of the matrix powder containing Mg is not particularly limited, and may be in the form of, for example, a powder, a chip, or a block.

Further, the matrix powder containing Mg includes an alloy containing Mg or a powder consisting of Mg alone.

When the matrix powder containing Mg is an alloy, Al, Zn, Mn, Zr, Ce, Li, and Ag may be included in addition to Mg. However, it is not limited to these.

More specifically, AZ31, AZ91 and the like can be used as the matrix powder containing Mg.

As described above, the particle size and shape of the Si powder are not particularly limited. However, the particle size is preferably from 10 to 500 μιη, more preferably from 10 to 200 m. The shape is preferably a chip, a small piece, a lump or the like in addition to a sphere or a powder.

In the preparation process, the ratio of the weight of Si to the weight of Mg contained in the matrix powder, that is, (weight of Si powder) no (weight of Mg in matrix powder) 1 36.6 / 63. It should be: If the added amount of Si exceeds 36.6% by weight, all of the Mg in the matrix powder becomes theoretically Mg ₂ Si (that is, Mg as a matrix does not remain). The material obtained in this case has a significantly lower strength and does not have the desired properties. Therefore, (weight of Si powder) / (weight of Mg in matrix powder) Force 36.6 / 63.4 or less, preferably 10/90 or less from the viewpoint of mechanical properties and machinability There should be.

A composite powder in which Si is dispersed in the matrix powder by mixing the matrix powder containing Mg and the silicon Si powder is prepared.

Here, the preparation step includes _a ) _a step of blending the Si powder and the matrix powder to obtain a blended powder; and b) a step of pulverizing and / or crimping the obtained blended powder and Z or crushing. Is good. Further, the step b) is preferably repeated a plurality of times. Also, the step b) is preferably performed using a crusher. The crusher should have a mechanical crushing capacity utilizing the impact energy of Pall Media. For example, it is better to be selected from the group consisting of a rotating pole mill, a vibrating pole mill, and a planetary pole mill. By performing such mechanical pulverization, mixing, pressing, and crushing, the Si powder can be finely pulverized and dispersed in the matrix powder. This also increases the specific surface area of the Si particles and can increase the contact area with Mg, further promoting the reaction between Si and Mg.

FIG. 3 is a schematic diagram of the composite powder sample obtained in the preparation step, and FIG. 4 is an observation image of the composite powder sample actually obtained in the preparation step by an optical microscope. FIG. 3 shows that the Si particles are dispersed in the matrix. Similarly, Fig. 4 shows that Si particles (white) are dispersed in the matrix (black background).

The preparation process can be performed in various environments, for example, in the air. From the viewpoint of suppressing oxidation, it is preferable to perform the treatment in an inert gas atmosphere such as nitrogen gas or argon gas.

Next, the obtained composite powder is filled in a container and pressurized to produce a green compact or a magnesium-based composite material precursor.

The pressure in the filling and pressurizing step is preferably 4 t / ⁷ cm ² or more and 8 t / cm ² or less. The reason for the upper limit of the pressure is as follows. That is, increasing the pressure has little effect on increasing the density of the finally obtained composite material. Also, if the pressure is increased, adhesion between the mold used and the molded body occurs, which shortens the life of the mold, which is not preferable.

<Magnesium-based composite material precursor or green compact B>

The magnesium-based composite material precursor or the green compact of the present invention can be formed by the above-described preparation step and filling / pressing step.

The magnesium-based composite material precursor or the green compact of the present invention is obtained by differential scanning calorimetry. (DSC), 150-650. At C, preferably 150 to 350 ° C., an exothermic peak accompanying the synthesis reaction of Mg ₂ Si should be observed. As an example, Fig. 5 shows the DSC measurement results of the following three samples. 1) 63.4 g of pure Mg (particle size: Ι Ι Ι Ιμιη) as a matrix powder containing Mg; and 36.6 g of Si powder (particle size: 38 ^ 111) by a pole mill. Time crushing, mixing, and pressing 'crushing' yields a composite powder in which fine Si particles are dispersed in a matrix (matrix) of Mg powder. This powder was used as a sample according to the present invention without being compacted. 2) A sample (porosity: 9%) obtained by simply mixing the same components as in 1) and applying pressure at a pressure of 5.8 t / cm ² . 3) 1) and 2) the same ingredients were mixed in a single pressure 1. 8 TZC m ² and pressurized obtained sample (porosity: 5 2%). From Fig. 5, the sample of 1) is 150, though it is in the powder state without compacting. From around C to around 200 ° C, an exothermic peak associated with the synthesis reaction of Mg ₂ Si was observed. On the other hand, in the sample of 2), an exothermic peak due to the synthesis reaction of Mg ₂ Si was observed at around 500 ° C. In 3), an endothermic peak was observed at 650 ° C (melting point of Mg) accompanying the melting point of Mg. From this, it can be seen that the sample of 1) has a temperature lower than the melting point of Mg, and Mg ₂ Si is synthesized at a significantly lower temperature than the sample of 2).

By heating the above-mentioned precursor or green compact, Mg ₂ Si is generated by the reaction of Mg in the matrix powder with the Si powder, and the mag and shim-based composite material of the present invention is obtained. be able to. '

The heating atmosphere is not particularly limited. However, in order to suppress the oxidation of Mg or Mg-containing alloy in the matrix (precursor or green compact), the heating atmosphere may be an inert gas atmosphere such as nitrogen or argon, or a vacuum. Good to do.

As can be seen from the DSC results in FIG. 5 described above, the heating temperature is preferably set to 150 ° (or more and 350 ° C. or less). In order to synthesize Mg ₂ Si in a relatively short time, However, the heating temperature is desirably 200 ° C or higher.

Note that it is preferable to hold at a certain temperature for a certain time depending on the shape and dimensions of the precursor or the green compact. In particular, during the heating step, it is preferable to prevent non-uniform generation of Mg ₂ Si particles due to a temperature difference between the surface layer and the inside of the precursor or the green compact. Good. On the other hand, it is preferable to suppress the coarse growth of the Mg ₂ Si particles and the Mg crystal grains by increasing the holding time. The holding time depends on the shape and dimensions of the precursor or green compact, but is preferably 1 minute or more and 30 minutes or less.

The magnesium-based composite material of the present invention preferably further includes a plastic working step such as a warm forging method or a warm extrusion method as needed. This closes the porosity in the material, which can increase the density of the composite and further improve its mechanical properties. Specifically, a method in which the composite material immediately after the heating step is directly subjected to warm plastic working; and a method in which the composite material after the heating step is heated again and then subjected to warm plastic working can be exemplified. . However, the former method is advantageous from an economic point of view. <Magnesium-based composite material B>

The Mg ₂ Si thus obtained has the following characteristics.

The particle size of mg ₂ S i is 1 0~2 0 0 ί m, the M g ₂ S i particles are formed in a state of being dispersed in Maguneshiumu based composite material obtained.

Therefore, having the above-mentioned properties of Mg ₂ Si, the obtained magnesium-based composite material of the present invention has excellent properties, for example, mechanical properties and corrosion resistance. If the composite material having these excellent properties contains 100 wt% of Mg ₂ Si in the composite material, the content is preferably 3 wt% or more, and more preferably 5 wt%. In particular, the composite material of the present invention has a property of any one of the above-mentioned A) and B) or a property obtained by variously combining two or more kinds of the properties as described above.

In the present invention, the tensile strength can be measured by a method based on the JIS standard. Further, the tensile strength can be measured by a method described later in Examples. In other words, the tensile strength was determined by preparing a test piece with a diameter of 3.5 mm and a parallel part of 14 mm as a test sample, mounting this test piece on a 10-ton autograph, and setting the displacement rate to 0.5 mmZ. A tensile test can be performed by applying a tensile load, and the value obtained by dividing the load when the test piece breaks by the fracture area of the sample can be measured as the tensile strength.

By using the production method of the present invention, that is, the powder metallurgy method, it is possible to synthesize Mg ₂ Si in a solid state without causing a liquid phase of Mg to appear. As a result, Trittas Mg has fine crystal grains, and Mg ₂ Si is also finely dispersed in the matrix, making it possible to economically produce a magnesium-based composite material with the above excellent properties, such as excellent mechanical properties and corrosion resistance. It can be prepared well.

The dimensional change between the obtained composite material and the precursor or the green compact is small, for example, because it is manufactured in a process that does not pass through the liquid phase state of Mg. Therefore, the small dimensional change between the precursor and the composite material (ie, the final product) can be an advantage unlike the conventional method. Example

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the examples.

(Example 1)

As starting materials, 90 parts by weight of pure Mg powder (average particle diameter: 112 m) and 10 parts by weight of Si powder (average particle diameter: 64 Am) were prepared. After blending both, they were uniformly mixed using a Paul mill to obtain a mixed powder. The obtained mixed powder was filled in a circular mold having a diameter of 34 mm, and a load was applied within a range of a surface pressure of 2 to 7 t / cm ² to produce green compacts A-1 to A-7.

The following tubular furnace was prepared separately from the green compacts A-1 to A-7. That is, a tubular furnace into which nitrogen gas (gas flow rate: 3 dm ³ / min) was flown and whose temperature in the furnace was controlled at 580 ° C was prepared. The green compacts A-1 to A-7 obtained above were introduced into this tubular furnace, heated and maintained for 15 minutes, and immediately solidified to a relative density of 99% or more by a powder forging method to obtain a magnesium-based material. Composite materials B-1 to B-17 were obtained. The conditions of the powder forging method were: mold temperature: 250 ° C; surface pressure: 8 tZ cm ^2. Water-soluble lubrication was applied to the mold wall from the viewpoint of preventing solidification and adhesion of the mold. The agent was applied.

Table 1 shows the properties of the green compacts A-1 to A-7 and the magnesium-based composite materials B-1 to B-7 obtained above. In Table 1, “porosity” is a value calculated by the method described above. Also, Table 1 shows the reaction synthesis onset temperature of ₂ Si obtained by DS.C measurement (in Table 1, simply referred to as “reaction onset temperature”). The mechanical properties (hardness, tensile strength and elongation at break) of No, and magnesium based composite materials B-1 to B-7 are also shown.

The presence or absence of the Mg liquid phase was determined by observing whether or not there was an endothermic peak at around 65 ° C. in the DSC measurement results. That is, when there is an endothermic peak, it is due to the latent heat at the time of appearance of the liquid phase of Mg, and it was set as “Mg liquid phase” force S “Yes”.

The hardness, tensile strength and elongation at break were measured as follows. <Measurement of hardness>

The hardness was measured with a micro Vickers hardness tester under a load of 49 N. <Measurement of tensile strength>

A test piece having a diameter of 3.5 mm and a parallel portion of 14 mm was prepared as a test sample. This test piece was mounted on a 10-ton autograph, and a tensile test was performed by applying a tensile load at a displacement speed of 0.5 mm / min. The value obtained by dividing the load when the test piece fractured by the fracture area of the sample was defined as the tensile strength.

Measurement of elongation at break>

The elongation at break was calculated from the maximum displacement in a region (plastic deformation region) away from a straight line having a certain slope in the load-displacement curve sampled on the sheet of paper during the tensile test.

Table 1. Properties of green compact A-"! ~ 7 and composite material B-"! ~ 7

Run Green compacts Porosity Reaction initiation temperature M g Liquid phase composite ra 'material Mechanical properties

No. (%) (° C) Presence or absence Hardness H V Tensile strength (MPa) Elongation at break (%)

1 A—1 9.2 423 None B—1 1 23 267 4.4

2 A-2 15.3 452 None B-2 1 20 262 4.8

3 A—3 24.8 484 None B-3 1 1 8 260 4.9

4 A— 4 29.5 496 None B-4 1 1 4 258 4.2

5 A— 5 33.2 51 1 None B-5 1 1 2 251 3.8

6 A— 6 38.9 535 Yes B-6 1 07 202 2.1

7 A— 7 42.2 541 Yes B-7 1 04 1 97 1.7

Green compact A- 1 to 5 has a porosity in accordance with the present invention, by a Mochiiruko this, M g ₂ S i in a solid state without occurrence of the liquid phase of M g Could be formed. As a result, a composite material B-1 to 5 in which fine Mg ₂ Si was dispersed in a magnesium base was obtained. As shown in Table 1, the material had excellent mechanical properties. It was confirmed.

On the other hand, a green compact A- 6 and 7, the porosity has, to form a composite material have use this liquid phase not Mg ₂ S i is solid state only defined outside of the invention But it is formed. Accordingly, coarse Mg ₂ S i is formed composites B- 6 and 7 is obtained, whereby the mechanical properties of the composite material B- 6 and 7, as shown in Table 1, those markedly properly lowered Met.

(Example 2)

As starting materials, AZ91D magnesium alloy powder (average particle size: 61 // m; nominal composition: Mg—9A 1—l Zn / mass%) 8 5 parts by weight and Si powder (average particle size: 64 / m) 15 parts by weight were prepared. After blending both, the mixture was uniformly mixed using a pole mill to obtain a mixed powder. The obtained mixed powder was filled into a circular mold having a diameter of 11.3 mm, and a load of a surface pressure of 5 tZcm ² was applied to produce a green compact A-8. The measured porosity was 12.3%, which satisfied the range specified by the present invention.

The obtained green compact A-8 was heated and held at a ripening temperature shown in Table 2 for 30 minutes in a tubular furnace into which nitrogen gas (gas flow rate: 2 dm ³ / min) was introduced. Then, it was cooled down to room temperature in the furnace to obtain composite materials B-8 to B-14. With respect to this material B-8 to 14, the presence or absence of the synthesis of Mg ₂ Si and the remaining state of Si were confirmed by observing the structure with an optical microscope and performing X-ray diffraction. Table 2 also shows the results. Table 2. Properties of green compact A-8 and composite material B_8 ~ "! 4

As can be seen from the composite materials Β-8 to 1-12, it was confirmed that the reaction between Mg and Si progressed and Mg ₂ Si was synthesized by heating in an appropriate temperature range. Also, in these materials, it was confirmed that the added Si powder all contributed to the reaction with Mg, and as a result, the Si powder did not remain in the material after the Mg ₂ Si synthesis reaction.

On the other hand, as can be seen from the composite materials B-13 and 14, when the temperature range is lower than the appropriate heating temperature range, the reaction between Mg and Si does not proceed, and Mg ₂ Si is not synthesized. It was confirmed. In addition, it was confirmed that Si powder remained in the composite materials B-13 and 14.

(Example 3),

As starting materials, pure Mg powder (average particle size: 112 μm) and Si powder (average particle size: 64 ^ m) were prepared, and they were mixed so as to have the composition shown in Table 3. A mixed powder was obtained. The obtained mixed powder was filled in a circular mold having a diameter of 11.3 mm, and a load of a surface pressure of 6 t / cm ² was applied to produce green compacts A-9 to A-15. The porosity of each of these molded products A-9 to A-15 was measured to be 8.9 to 11%, which satisfied the range specified by the present invention.

A tubular furnace in which nitrogen gas (gas flow rate: 2 dm ³ / ni in) was introduced into the obtained green compacts A-9 to A-15, and wherein the temperature in the furnace was controlled to 580 ° C. It was placed in a furnace, heated and maintained for 30 minutes, and then cooled to room temperature in the furnace to obtain composite materials B-15 to B-21. Observe the appearance of this material B—15 to 21 and T / JP02 / 02968

The elements and compounds constituting the material were identified by X-ray diffraction measurement. _C The results are also shown in Table 3. Table 3. Properties of green compacts A-9-15 and composite materials B-15-21

By setting the mixing ratio of Mg and Si of the starting materials to a certain appropriate value (A-9-13), it is a composite material with good shape and appearance, containing Mg ₂ Si and Mg When the compounding ratio is not an appropriate value (A-14 and 15), a composite material containing Mg ₂ Si and Si can be obtained. Table 3 shows that it is possible to obtain materials (B-20 and 21) that do not have high strength and cause breakage during transportation.

(Example 4)

Prepare pure Mg powder (average particle size: 223 ^ m) and Si powder (average particle size: 105 m) as starting materials, mix them to achieve the composition shown in Table 4, and mix. A powder was obtained. The obtained mixed powder was filled in a circular mold having a diameter of 34 mm, and a load of a surface pressure of 6 tZcm ² was applied to produce green compacts A-16 to A-22. The porosity of the green compacts A-16 to 22 was 8.3 to 10.7%, which satisfied the range specified by the present invention.

The obtained green compact A-16 to 22 was converted into a tubular furnace into which a nitrogen gas (gas flow rate: 3 dm ³ / min) was introduced and the furnace temperature was controlled at 580 ° C. And heat it for 15 minutes * and hold it. Then, composite materials B-22 to B-28 were obtained. The conditions of the powder forging method were: mold temperature: 250 ° C, surface pressure: 8 t / cm ^2, and a water-soluble lubricant on the mold wall from the viewpoint of preventing adhesion between the solidified body and the mold. Was applied.

The average corrosion rates of the obtained composite materials B-22 to B-28 were measured. In this method, a cube (10 mm X 10 mm X thickness 1 Omm) was machined from each material B-22 to B-28, and polished with emery paper to obtain a test piece. The test pieces were evaluated for corrosion resistance by a 5% salt spray test (100 hr). The average corrosion rate was calculated from the weight change before and after the test and used as an index for corrosion resistance evaluation. Table 4 also shows the results. Table 4 also shows the amount of Mg ₂ Si (calculated from the composition). Table 4. Properties of green compacts A-16-22 and composite material B-22-28

Table 4 shows that composite materials B-22 to 26 have excellent corrosion resistance. On the other hand, it can be seen that the materials B-27 and 28 having a small amount of Mg ₂ Si have low corrosion resistance.

(Example 101)

As starting materials, 85 parts by weight of pure Mg powder (average particle size: 168 m) and 15 parts by weight of Si powder (average particle size: 5'8111) were prepared. After blending both, the powder was mechanically ground, mixed and pressed by using a rotating pole mill for 5 hours to obtain a composite powder X-101. The obtained composite powder X—101 was filled in a circular mold having a diameter of 34 mm, A green compact A-101 was produced by applying a load of a surface pressure of 6 tZcm ² . Further, a green compact A-102 having the same composition as that of the green compact A-101 was produced without performing a treatment using a rotary pole mill for 5 hours.

The following tubular furnace was prepared separately from the green compact A-101. That is, a tubular furnace into which nitrogen gas (gas flow rate: 3 dm ³ / ni i ri) was introduced and whose temperature was controlled in the vicinity of 100 to 500 ° C shown in Table 1 was prepared. . The green compact A-101 or A-102 obtained above was introduced into this tubular furnace, heated and maintained for 5 minutes, and immediately solidified by powder forging to obtain a relative density of 99% or more, and the magnesium was melted. The base composite materials B-101 to B-110 were obtained. The conditions for the powder forging method were: mold temperature: 250 ° C; surface pressure: 8 tZcm ^2. From the viewpoint of preventing adhesion between the solidified body and the mold, water-soluble lubrication was applied to the mold wall surface. The agent was applied.

Table 101 shows the properties of the green compacts A-101 or A-102 and the magnesium-based composite materials B-101 to B-110 obtained above. In Table 101,

“Presence or absence of Mg ₂ Si” was observed by X-ray diffraction. The “hardness” is a value measured by a scale E Rockwell measuring instrument. Table 101. Properties of green compacts A-101-102 and composite materials B-102-110

R n No—101 to 105, the composite powder according to the present invention is used, and the heating temperature is as low as 150 ° C. to 343 ° C., so that a high hardness composite material can be obtained. Run Nos. 106-107 use the composite powder according to the present invention. Therefore, generation of Mg ₂ Si was confirmed, but the hardness was lower than desired. This is probably because the heating temperature was too high and the Mg ₂ Si particles grew coarsely. Further, Run No. 108 uses the composite powder according to the present invention, but since the heating temperature is too low, generation of Mg ₂ Si cannot be confirmed and, of course, the hardness is insufficient. Was. In Run Nos. 109 to 110, generation of Mg ₂ Si was not confirmed because the composite powder according to the present invention was not used and the heating temperature was too low. Of course, the hardness was also insufficient.

(Example 102)

• As starting materials, 90 parts by weight of AZ91D magnesium alloy powder (average particle size: 61 μm; nominal composition: Mg—9A1—lZnZma ss%) and Si powder (average particle size: 64 πι) 10 Parts by weight. After blending both, mechanical crushing, mixing and compression treatment were performed for 4 hours using a vibration ball mill to obtain a composite powder. The obtained composite powder was filled in a circular mold having a diameter of 34 mm, and a load of a surface pressure of 6 tZ cm ² was applied to produce a green compact A-103.

Further, although the composition was the same as that of the green compact A-103, the green compact A-104 was produced without performing the vibration pole mill treatment for 4 hours.

The following tubular furnace was prepared separately from the green compact A-103 or A-104. That is, a tubular furnace into which nitrogen gas (gas flow rate: 3 dmVmin) was introduced and whose temperature in the furnace was controlled at around 80 to 530 ° C shown in Table 1 was prepared. The green compact A-103 or A-104 obtained above was introduced into this tubular furnace, heated and maintained for 5 minutes, and immediately solidified by powder forging to a relative density of 99% or more, and the magnesium-based composite material was obtained. B—11 1 to B—120 were obtained. The conditions of the powder forging method, mold temperature: 250 ° C;及Pimen圧: 8 t a Bruno cm ^2, solidified and the mold wall from the viewpoint of adhesion prevention of the mold soluble Lubricant was applied.

Table 102 shows the properties of the green compacts A-103 or A-104 and the magnesium-based composite materials B-11 to B-120 obtained above. In Table 102, “presence / absence of Mg ₂ Si” was observed by X-ray diffraction. “Hardness” is a value measured by a scale E Rockwell measuring device as described above. Table 102. Properties of green compacts A-103-104 and composite material B-111-120

R n No. 1 11 to 1 15 use the composite powder according to the present invention, and have a heating temperature of .150 ° C. to 346 ° C. to obtain a high hardness composite material. Came out. In Run Nos. 116 to 117, since the composite powder according to the present invention was used, generation of Mg ₂ Si was confirmed, but the hardness was lower than desired. This is probably because the heating temperature was too high and the Mg ₂ Si particles grew coarsely. Further, Run No. 118 uses a composite powder according to the present invention, but since the heating temperature is too low, generation of Mg ₂ Si cannot be confirmed and, of course, the hardness is insufficient. there were. In Run Nos. 109 to 110, generation of Mg ₂ Si was not confirmed because the composite powder according to the present invention was not used and the heating temperature was too low. Of course, the hardness was also insufficient.

(Example 103)

A disk (diameter 50 mm, thickness 3 mm) made of pure Mg (purity 99.85%) and the composite powder X-101 of Example 101 were prepared. Prepare a state in which the composite powder X-101 is placed on one side of a disk, and introduce it into a furnace controlled at 160 ° C into which nitrogen gas (gas flow rate: 3 dm ³ / min) has been introduced. And heated and held for 5 minutes. Then, a surface pressure of 8 tZcm ² was applied using a hydraulic press to produce a clad plate material in which the magnesium-based composite powder was in close contact with the magnesium circular plate. Again, put it in a furnace under a nitrogen gas atmosphere After insertion, temperature: 250 ° C., holding time: 10 minutes.

The obtained composite material was checked for the presence of Mg ₂ Si peaks by X-ray diffraction, polished with emery paper, and evaluated for corrosion resistance by a 5% salt spray test (lOOhr). The average corrosion rate was calculated from the weight change before and after the test, and used as an index for corrosion resistance evaluation.

As a result of X-ray diffraction, a peak of Mg ₂ S i was confirmed on the surface on the side where the composite powder X—101 was placed and clad. In addition, according to observation with an optical microscope, the magnesium-based composite material and magnesium as the base material were in a favorable bonding state. On the other hand, on the surface on which the composite powder X-101 was not placed, as a result of XRD, no Mg ₂ Si peak was observed and only a magnesium peak was observed.

As a result of the corrosion resistance test, the average corrosion rate on the surface on the clad side was 0.014 g nom ² Zhr, while that of the non-clad Mg plate material was 0.21 g / m ² / hr. Was. That is, it was confirmed that the corrosion resistance was significantly improved by cladding the magnesium-based composite material. Industrial applicability

Since the magnesium-based composite material of the present invention has high strength, high abrasion resistance and high corrosion resistance in addition to weight reduction, for example, structural component materials such as automobile parts and home electric appliance parts where these properties are desired simultaneously. And it can be used as medical welfare or protective equipment such as nursing beds, wheelchairs, canes, and walking cars.

Further, the magnesium-based composite powder used in the production method of the present invention can be applied as follows. That is, while being placed on the magnesium alloy plate, plastic working such as pressurization / compression / "rolling" is performed at room temperature or warm temperature, and then the heating step used in the present invention is provided. can Maguneshiumu based composite powder of the present invention is to produce a clad sheet was pressure bonded. that is, only the magnesium alloy sheet table surface, a clad plate of Mg ₂ S i particles are dispersed, the Mg ₂ S i particles it can be prepared Maguneshiumu alloy plate and firmly bonded to that plate. the clad sheet has excellent corrosion resistance and wear resistance by uniform dispersion of M g ₂ S i particles particles, structural lightweight piping Can be used as a part.

Claims

The scope of the claims

1. a step of preparing a mixed powder by blending a matrix powder comprising magnesium (Mg) and a silicon (Si) powder; filling the mixed powder into a container and pressurizing to increase the porosity to 35 5 % Of the green compact; heating and holding the green compact in an inert gas atmosphere or vacuum; and reacting the magnesium powder with the Si in the matrix powder by magnesium silicide. A method for producing a magnesium-based composite material, comprising: producing (Mg ₂ Si).

2. The method according to claim 1, wherein the Mg ₂ Si is dispersed in the magnesium-based composite material.

3. The method according to claim 1, wherein in the preparation step, (weight of Si powder) no (weight of Mg in the matrix powder) is 36.6 / 63.4 or less.

4. The method according to claim 1, wherein the heating is performed at 350 ° C. or higher.

5. The method according to any one of claims 1 to 4, wherein the Mg ₂ Si is 3 w1:% or more when the magnesium-based composite material is 100 wt%.

6. A magnesium-based composite material precursor obtained by blending a matrix powder containing magnesium (Mg) and a silicon (Si) powder, wherein the precursor has a porosity of 35% or less. Matrix composite precursor.

7. The precursor according to claim 6, wherein the precursor has an exothermic peak derived from Mg ₂ Si at 350 to 650 ° C in differential scanning calorimetry (DSC) measurement.

8. The precursor according to claim 6, wherein the precursor has a ratio of (weight of Si powder) / (weight of Mg in matrix powder) of 36.6 / 63.4 or less.

9. A magnesium-based composite precursor obtained by mixing a matrix powder having magnesium (Mg) and a silicon (Si) powder, wherein the precursor is measured by differential scanning calorimetry (DSC). The magnesium-based composite precursor having an exothermic peak derived from Mg ₂ Si at 350 to 650 ° C.

10. The precursor according to claim 9, wherein the precursor has a ratio of (weight of Si powder) / (weight of Mg in matrix powder) of 36.6 / 63.4 or less.

1 1. Matrix powder containing magnesium (Mg) and silicon (S i) a step of preparing a mixed powder by blending with a powder; and a step of filling the mixed powder into a container and pressurizing to produce a magnesium-based composite material precursor having a porosity of 35% or less. A method for producing a magnesium-based composite material precursor.

12. The method according to claim 11, wherein in the preparation step, (weight of Si powder) Z (weight of Mg in the matrix powder) is 36.6 / 63.4 or less.

1 3. A magnesium-based composite material in which magnesium silicide (Mg ₂ S i) is dispersed in a matrix having magnesium (Mg), wherein at least one selected from the following A) and B) Magnesium based composite material with one kind of properties

A) The magnesium based composite material has a Rockwell hardness (E scale) of 40 or more and 95 or less, and / or the magnesium based composite material has a Rockwell hardness (E scale) of magnesium of the magnesium based composite material. Greater than the Rockwell hardness (E scale) of the base material excluding silicide by a value of 20 or more and 40 or less; and

B) The tensile strength of the magnesium-based composite material is 10 OMPa or more and 28 OMPa or less, and / or the tensile strength of the magnesium-based composite material is 2 OMPa or more and 5 OMPa or less than the tensile strength of the base material. Big in.

14. The material according to claim 13, wherein the Mg ₂ Si is 3 wt% or more when the magnesium-based composite material is 100 wt ° / ₀ .

1 5. A step of blending a matrix powder comprising magnesium (Mg) and a silicon (Si) powder to prepare a composite powder in which Si is dispersed in the matrix powder; and A method for producing a magnesium-based composite material, comprising a step of generating magnesium silicide (Mg ₂ S i) by heating and maintaining a powder in an inert gas atmosphere or vacuum.

16. After the preparation step, the method further comprises the step of filling the composite powder into a container and pressurizing to produce a green compact, and heating and holding the green compact to form a magnesium silicide (Mg ₂ S 16. The method of claim 15, further comprising the step of:

1 7. The Mg ₂ S i is claim 1 5 or 16 method wherein are dispersed in the magnesium-based composite material.

18. The preparation step comprises: a) a step of blending the Si powder and the matrix powder to obtain a blended powder; and b) a step of crushing and Z or pressing and crimping or crushing the blended powder. 15. The method according to any one of 15 to 17.

19. The method of claim 18, wherein said preparing step further comprises the step of repeating b) a plurality of times.

20. The method according to claim 18 or 19, wherein the step b) of the preparing step is performed using a pulverizer.

21. The method according to claim 20, wherein the pulverizer has a mechanical pulverization processing capacity utilizing impact energy by a ball media.

22. The method according to claim 20 or 21, wherein the powder is selected from the group consisting of a rotary pole mill, a vibrating pole mill, and a planetary pole mill.

23. The method according to any one of claims 15 to 22, wherein in the preparation step, (weight of Si powder) no (weight of Mg in the matrix powder) is 36.6 / 63.4 or less. .

24. The method according to any one of claims 15 to 23, wherein the heating is performed at 150 ° C or higher and 350 ° C or lower.

25. The method according to any one of claims 15 to 24, wherein the Mg ₂ S i is 3 wt% or more when the magnesium-based composite material is 100 wt%.

26. Magnesium-based composite material precursor obtained by blending a matrix powder containing magnesium (Mg) and a silicon (Si) powder and dispersing the Si powder in the matrix powder . '

2 7. The precursor, in differential scanning calorimetry (DSC) measurement, the precursor of claim 26 having an exothermic peak derived from Mg ₂ S i to 1 50~35 0 ° C.

28. The precursor according to claim 26 or 27, wherein the precursor has (weight of Si powder) Z (weight of Mg in the matrix powder) of 36.6 / 63.4 or less.

2 9. A magnesium-based composite material precursor obtained by blending a matrix powder having magnesium (Mg) and a silicon (S i) powder, wherein the precursor is a differential scanning calorimeter (DSC) A magnesium-based composite precursor having an exothermic peak derived from Mg ₂ Si at 150 to 350 ° C. in the measurement.

30. The precursor according to claim 29, wherein the precursor has a ratio of (weight of Si powder) / (weight of Mg in matrix powder) of 36.6 / 63.4 or less.

3 1. A process of blending a matrix powder containing magnesium (Mg) and a silicon (Si) powder to prepare a composite powder in which Si is dispersed in the matrix powder; A method for producing a magnesium-based composite material precursor, comprising a step of filling a composite powder into a container and pressurizing the container to produce a magnesium-based composite material precursor.

3 2. The preparing step includes a) a step of blending the Si powder and the matrix powder to obtain a blended powder; and b) a step of crushing and / or pressing and blending or crushing the blended powder. 32. The method of claim 31.

33. The method according to claim 32, wherein said preparing step further comprises a step of repeating step b) a plurality of times.

34. The method according to claim 32 or 33, wherein the step b) of the preparing step is performed using a pulverizer.

35. The method according to claim 34, wherein the crusher has a mechanical crushing capacity utilizing impact energy from ball media.

36. The method according to claim 34 or 35, wherein the crusher is selected from the group consisting of a rotary pole mill, a vibrating pole mill, and a planetary ball mill.

3 7. The method according to any one of claims 31 to 36, wherein in the preparation step, (weight of Si powder) / (weight of Mg in matrix powder) is 36.6 / 63.4 or less. the method of.

38. A magnesium-based composite material in which magnesium silicide (Mg ₂ S i) is dispersed in a matrix having magnesium (Mg), wherein at least one selected from the following A) and B) Magnesium-based composite material having the following characteristics:

A) The Rockwell hardness (E scale) of the magnesium-based composite material is 40 or more and 105 or less, and / or the Rockwell hardness (E scale) of the magnesium-based composite material is magnesium silicide of the magnesium-based composite material. Exceeding the Rockwell hardness (E scale) of the base material excluding the value of 20 to 80; B) The tensile strength of the magnesium-based composite material is 10 OMPa or more and 35 OMPa or less, and the tensile strength of Z or the magnesium-based composite material is 2 OMPa or more and 10 OMPa or less than the tensile strength of the base material. Large in value.

3 9. The M g ₂ S i, the Maguneshiumu group when the composite material with 1 00 wt%, material according to claim 38, wherein at 3 wt% or more.